1. Field of the Invention
The present invention relates to an apparatus and method for monitoring optical obstructions in a passive optical network; and, particularly, relates to an apparatus and method for monitoring optical fibers and measuring obstruction locations in a passive optical network by integrating optical filters having specific wavelength and monitoring a monitoring-waveband reflector to filter and reflect inputting lights, achieving the simplicity and high efficiency.
2. Description of the Prior Art
As a result of the rapid growth of the global Internet, conventional networks cannot handle demands from high-speed data transformation applications due to the revolution in communication industry. Technologies in the developed optoelectronics industry and various applications for different products have timely provided a best solution in response to a demand for large bandwidth in the rapid growth of the global Internet, high-quality media network, and variety of data communications. Various architectures for optical communication network are successively developed and the passive optical network service system is most attended. Therefore, it is necessary to develop an apparatus and method for monitoring respective branches line in a passive optical network to cope with the demands of monitoring in particular network architectures in the future.
It is not easy to monitor optical fibers in a passive optical network according to an original design of branch line. In the past, the manner of monitoring that uses the Optical Time Domain Reflectometer (OTDR) was commonly adopted. However, all divergent signals in a locus chart of the OTDR are overlapped and any one of the signals cannot thus be identified alone. To solve such an identification problem, adding an additional active-identifying component is employed but the interaction between a communication network and a host computer in the central office is required, normally augmenting the complexity of the monitoring system; additionally, using excess length shifted fiber with a reflecting element as an identifying component is also employed, but it is difficult in design and installation since the branches line are different in length. Such the monitoring manner by using the OTDR is hardly to be accomplished because of the limitation of the Dynamic Range and the Event Dead Zone of the OTDR when the number of the branches line increases.
Additionally, a tunable laser light source, circulator device, and light power meter are also employed in a terminal side with the fiber bragg grating (FBG) fiber which may reach the goal of detecting obstructions though but cannot simultaneously display a real time status of all routes as measuring each branch line. Instead, the tunable laser light source has to cyclically switch to different wavelength monitored, consuming a lot of time when a great number of branch line. Taking this approach may be aware of the split route being obstructed but may not identify a location of the obstruction, remaining a restriction in maintenance.
In view of the above, the conventional stuff still has a lot of drawbacks to be fine-designed goods and should be improved.
Upon the drawbacks incurred by the above conventional goods, the inventor of the present invention has given every effort in reformation and innovation. After years of painstaking efforts, finally, an apparatus and method of monitoring optical obstructions in an passive optical network has been successfully developed.